Two myasthenia gravis patients developed nephrotic syndrome due to minimal change glomerulopathy 3 to 14 years after thymectomy for malignant thymoma. Impaired cellular and humoral immunity has been documented in patients with thymoma and persists after thymectomy. The occurrence of minimal change disease lends support to the hypothesis that the glomerulopathy is secondary to T-cell dysfunction, resulting in production of a lymphokine which increases glomerular basement membrane permeability.